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Peter Perkins


MathWorks

985 total contributions since 2011

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Answered
Devide a table in several tables by criteria
You can do this in several ways, but honestly the most straight-forward is to write a loop, as shown below. The real question is...

5 days ago | 1

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Answered
Two "Time" colunm in a time table
Correct, there is only one vector of times to label the rows of a timetable. But that's not to say you can't put both vectors in...

6 days ago | 0

| accepted

Answered
split timetables into multiple hourly timetables and save as separate .mat files
You can do this in several ways, but honestly the most straight-forward is to write a loop, as shown below. The real question is...

6 days ago | 0

Answered
Separating tables in tables after importing
Walter is correct, it's probaby not a good idea to split the table into separate workspace variables. And as he also says, it's ...

6 days ago | 0

Answered
time formate changes while exporting table as excel
S.M., are you quite sure this is not simply a formatting issue in the spreadsheet? When I run this code in a recent version of M...

6 days ago | 0

Answered
How to fix the missing patches that turn into NAT?
It's possible that what's happening is that your timestamps are stored in the spreadsheet file as text, not as dates, and that s...

12 days ago | 0

Answered
Bar plot using multiple table variables?
It's not completely clear what you are asking for, but my guess is that you want bar, with the 'stacked' input, and t{2:7,2:4} a...

13 days ago | 0

Answered
how to identify unique columns, based on the first two rows, make an average of the uniques columns and remove the duplicate columns?
You may have a reason for wanting row-oriented data, but I'm gonna suggest that you transpose your data, create a table, and use...

13 days ago | 0

Answered
How to pivot the table
At first glance, this seems like you could be using the unstack function, and it may be that you can. But you are a bit out of m...

13 days ago | 0

Answered
Plotting two different dimensions time series data on the same x-axis
>> x1 = rand(1,6); t1 = datetime(2019,6,12,1:6,0,0,0); >> x2 = rand(1,24); t2 = datetime(2019,6,12,1,(0:23)*15,0); >> plot(t1,...

13 days ago | 0

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Answered
Creating a for loop to see if date exists
Also, it may be that you need to "find that date and find the position of where it is located" because you'll then use that loca...

13 days ago | 0

Answered
How to import text to timetable with ntsf timestamp
"it only accepts a number formated as uint64" NTFS timestamps are defined as 64bit numbers. Anything smaller than that and you ...

19 days ago | 0

Answered
How to ensure my times will follow daylight savings?
The answer is don't use datenums. They do not support time zomes at all. Use datetimes. If you set the TimeZone property on you...

21 days ago | 0

Answered
Round down to a chosen hour-min-sec time at a date
Since you're working in liear time (preserving dates) and no in circular time (caring only about time of day), I would think dis...

21 days ago | 0

Answered
Plotting date time Hear rate and Stress in the same plot and/or in different plots
After a bit of cleaning up, I get this timetable: >> TT = readtimetable('SHS.csv'); >> TT.Time.Format = "dd-MMM-yyyy"; >> TT....

21 days ago | 1

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Answered
How to add datetime from seconds?
That's not the error that I get, but it's possible that you are using an older version with different error handling. In any ca...

21 days ago | 1

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Answered
Split timetable using retime
You are using datetimes, which is a linear time line. It sounds like you want "time of day", which is a circular time line. I ca...

21 days ago | 0

Answered
How to import text to timetable with ntsf timestamp
In recent versions (since R2018a? or thereabouts): >> help datetime [snip] D = datetime(X,'ConvertFrom',TYPE) converts the nu...

21 days ago | 0

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Answered
How to identify entries for a time frame?
The data in your example are VERY sparse, and it's hard to know if that's typical or not. One very simple way to do what you wa...

1 month ago | 0

Answered
How can I extract data from a table and put it into a new one?
With no example, it's hard to understand what you have and what you want to end up with, but your description sounds very much l...

1 month ago | 0

Answered
extract data for a specified date and time period
Abhishek, you have not made clear what problem you are actually running into. One of the problems is that every 400 rows or so, ...

1 month ago | 2

Answered
extract column name of table with Nan column
Using {:,:} to convert the entire table to a homogeneous array is perhaps one way to do this, but scales badly very quickly as t...

1 month ago | 0

Answered
export cell2table to excel
cell2table is a unction that converts a cell array to 1 table. writetable is a function that writes a table to a file. This Su...

1 month ago | 0

Answered
Undefined operator '-' for input arguments of type 'table'.
Tables are containers, and can contain (almost) any data type. So they do not support all the methods that their contents suppor...

1 month ago | 0

Answered
deleting all rows from a table that contain a string
Eth, I think the more important question is how you got yourself into this corner to begin with. You say you have a table, But i...

1 month ago | 0

Answered
missing data, time series
All you need to do is call retime and tell it what you want the new time v ecgtor to be. Sometimes it's as simple as 'hourly', o...

1 month ago | 0

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Answered
How to get difference between two time values ?
Don't use etime. Use datetimes. Haritha, without more info it's hard to tell, but it looks like your "data" is a cellarray of ch...

1 month ago | 0

Answered
Get time/date online
I've taken the liberty of updating Vincent's soln's with soemthing more current (and in the second case, more straight-forward a...

1 month ago | 0

Answered
Categorical2Num in a table
If you are computing the average of a numeric variable using a cate3gorical variable to group your data, then you should not nee...

1 month ago | 0

Answered
How to extracy table rows by date?
Looking at your code, you seem to be creating a timetable with no data, just row times. That doesn't seem useful. But then "arra...

1 month ago | 0

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